Alternator assemblies are employed in many devices and/or apparatuses and are generally effective to selectively provide electrical current to many elements and/or components which are operatively contained within these devices and/or apparatuses.
Particularly, alternator assemblies typically include a selectively movable rotor which is movably contained or deployed within a housing. The housing typically includes and/or employs a stator which cooperates with the selectively movable rotor to provide electrical current and energy. While these alternator assemblies do provide electrical energy, they suffer from some drawbacks.
For example and without limitation, the housing of many alternator assemblies is typically formed from aluminum material and the rotor is typically formed from commercially available and conventional steel material. A "rear" steel bearing assembly having a first portion which is typically "press fit" into the "rear" or "back" alternator assembly housing and a second portion which is "press fit" onto the rotor shaft is usually employed to operatively support the rotor in the "rear" or "back" alternator assembly housing.
Since the thermal coefficient of expansion of aluminum is much greater than that of steel, a gap is typically formed between the first portion of the steel bearing assembly and the alternator housing which causes the contained rotor shaft to be unsecured or loosely secured within the rear or back alternator housing, thereby undesirably decreasing the overall performance of the alternator.
To address the previously delineated drawback, a material such as plastic or thermoplastic is typically formed into a cup and is placed over the first portion of the steel bearing assembly and is "fit" (e.g., press fit, transitionally fit, or slip fit) into the rear alternator assembly housing. The plastic material has a coefficient of expansion which is relatively larger than the aluminum material of the rear alternator assembly housing and selectively expands in order to "fill the gap" which is formed between the first portion of the steel bearing assembly and the alternator assembly housing. Alternatively, grooves are formed or "cut" into the first portion of the bearing assembly and the plastic material is selectively molded into these selectively formed grooves to form what is often referred to as "expansion coefficient bands". While the applied plastic material does provide for a more secure fit of the rotor shaft into the rear alternator assembly housing, the technique also suffers from several drawbacks.
For example and without limitation, the use of such a plastic cup or sleeve undesirably increases overall production cost and complexity. The use of selectively formed grooves also undesirably increases overall production costs. Further, the utilized plastic materials are relatively efficient insulators and undesirably prevent heat from being easily and efficiently dissipated from the bearing assembly, thereby undesirably decreasing the operating life of the bearing assembly and the alternator assembly. Further, the applied plastic material "creeps" and/or moves over time, thereby causing undesirable misalignment between the rotor and the stator.
To overcome these drawbacks, one attempt has been made to create and operatively use a steel cup which is selectively placed over the bearing assembly and which is selectively attached or fastened into the alternator assembly. While this steel cup overcomes the previously delineated "creep" and heat dissipation drawbacks, it requires several fasteners which increase the overall production cost and complexity of the production or manufacturing processes.
There is therefore a need for a new and improved alternator assembly which overcomes some or all of the previously delineated drawbacks of prior alternator assemblies.